A cremone bolt latching mechanism is a locking mechanism for a door to link two long vertical surface bolts together so that they can be operated in tandem with a knob or lever. Two bolts extend to a cremone operator, i.e., the mechanism that moves the actual bolts. A first bolt extends from the top of the door to the center mounted cremone operator and a second bolt extends from the bottom of the door to the center mounted cremone operator. A cremone bolt mechanism typically is designed to operate with either door knobs or door levers. If door levers are used, the lever is lifted from a horizontal position and rotated about the lever's spindle approximately ninety degrees to retract both the first and the second bolts at the same time. If knobs are used, the knob is rotated (with the top typically rotating towards the lock side of the door) through 180 degrees of rotation to retract both bolts at the same time. The mechanism needs to be adjusted or otherwise modified to change the direction of rotation for either left hand doors or right hand doors.
Past cremone operators were set from the factory for either left hand or right hand operation. They have been manufactured as either knob operators or lever operators. Changing hands required disassembling the mechanism, changing the location of springs and detent balls and or stop pins. Often the parts are reassembled incorrectly or lost all together. Cremone operators for knobs have not been convertible to levers and vice versa.
It would be beneficial to have a cremone bolt mechanism that enables use of a single cremone operator that allows for both lever and knob configurations (i.e., ninety or one hundred eighty degree rotation) and for both left and right opening doors.